1829 lines
44 KiB
C
1829 lines
44 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/mm/nommu.c
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*
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* Replacement code for mm functions to support CPU's that don't
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* have any form of memory management unit (thus no virtual memory).
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*
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* See Documentation/admin-guide/mm/nommu-mmap.rst
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*
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* Copyright (c) 2004-2008 David Howells <dhowells@redhat.com>
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* Copyright (c) 2000-2003 David McCullough <davidm@snapgear.com>
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* Copyright (c) 2000-2001 D Jeff Dionne <jeff@uClinux.org>
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* Copyright (c) 2002 Greg Ungerer <gerg@snapgear.com>
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* Copyright (c) 2007-2010 Paul Mundt <lethal@linux-sh.org>
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*/
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include <linux/export.h>
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#include <linux/mm.h>
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#include <linux/sched/mm.h>
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#include <linux/mman.h>
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#include <linux/swap.h>
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#include <linux/file.h>
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#include <linux/highmem.h>
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#include <linux/pagemap.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/backing-dev.h>
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#include <linux/compiler.h>
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#include <linux/mount.h>
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#include <linux/personality.h>
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#include <linux/security.h>
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#include <linux/syscalls.h>
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#include <linux/audit.h>
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#include <linux/printk.h>
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#include <linux/uaccess.h>
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#include <linux/uio.h>
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#include <asm/tlb.h>
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#include <asm/tlbflush.h>
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#include <asm/mmu_context.h>
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#include "internal.h"
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void *high_memory;
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EXPORT_SYMBOL(high_memory);
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struct page *mem_map;
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unsigned long max_mapnr;
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EXPORT_SYMBOL(max_mapnr);
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unsigned long highest_memmap_pfn;
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int sysctl_nr_trim_pages = CONFIG_NOMMU_INITIAL_TRIM_EXCESS;
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int heap_stack_gap = 0;
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atomic_long_t mmap_pages_allocated;
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EXPORT_SYMBOL(mem_map);
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/* list of mapped, potentially shareable regions */
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static struct kmem_cache *vm_region_jar;
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struct rb_root nommu_region_tree = RB_ROOT;
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DECLARE_RWSEM(nommu_region_sem);
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const struct vm_operations_struct generic_file_vm_ops = {
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};
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/*
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* Return the total memory allocated for this pointer, not
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* just what the caller asked for.
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*
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* Doesn't have to be accurate, i.e. may have races.
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*/
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unsigned int kobjsize(const void *objp)
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{
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struct page *page;
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/*
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* If the object we have should not have ksize performed on it,
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* return size of 0
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*/
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if (!objp || !virt_addr_valid(objp))
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return 0;
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page = virt_to_head_page(objp);
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/*
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* If the allocator sets PageSlab, we know the pointer came from
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* kmalloc().
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*/
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if (PageSlab(page))
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return ksize(objp);
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/*
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* If it's not a compound page, see if we have a matching VMA
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* region. This test is intentionally done in reverse order,
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* so if there's no VMA, we still fall through and hand back
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* PAGE_SIZE for 0-order pages.
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*/
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if (!PageCompound(page)) {
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struct vm_area_struct *vma;
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vma = find_vma(current->mm, (unsigned long)objp);
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if (vma)
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return vma->vm_end - vma->vm_start;
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}
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/*
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* The ksize() function is only guaranteed to work for pointers
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* returned by kmalloc(). So handle arbitrary pointers here.
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*/
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return page_size(page);
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}
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/**
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* follow_pfn - look up PFN at a user virtual address
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* @vma: memory mapping
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* @address: user virtual address
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* @pfn: location to store found PFN
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*
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* Only IO mappings and raw PFN mappings are allowed.
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*
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* Returns zero and the pfn at @pfn on success, -ve otherwise.
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*/
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int follow_pfn(struct vm_area_struct *vma, unsigned long address,
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unsigned long *pfn)
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{
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if (!(vma->vm_flags & (VM_IO | VM_PFNMAP)))
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return -EINVAL;
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*pfn = address >> PAGE_SHIFT;
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return 0;
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}
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EXPORT_SYMBOL(follow_pfn);
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LIST_HEAD(vmap_area_list);
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void vfree(const void *addr)
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{
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kfree(addr);
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}
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EXPORT_SYMBOL(vfree);
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void *__vmalloc(unsigned long size, gfp_t gfp_mask)
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{
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/*
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* You can't specify __GFP_HIGHMEM with kmalloc() since kmalloc()
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* returns only a logical address.
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*/
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return kmalloc(size, (gfp_mask | __GFP_COMP) & ~__GFP_HIGHMEM);
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}
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EXPORT_SYMBOL(__vmalloc);
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void *__vmalloc_node_range(unsigned long size, unsigned long align,
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unsigned long start, unsigned long end, gfp_t gfp_mask,
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pgprot_t prot, unsigned long vm_flags, int node,
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const void *caller)
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{
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return __vmalloc(size, gfp_mask);
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}
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void *__vmalloc_node(unsigned long size, unsigned long align, gfp_t gfp_mask,
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int node, const void *caller)
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{
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return __vmalloc(size, gfp_mask);
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}
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static void *__vmalloc_user_flags(unsigned long size, gfp_t flags)
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{
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void *ret;
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ret = __vmalloc(size, flags);
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if (ret) {
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struct vm_area_struct *vma;
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mmap_write_lock(current->mm);
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vma = find_vma(current->mm, (unsigned long)ret);
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if (vma)
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vm_flags_set(vma, VM_USERMAP);
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mmap_write_unlock(current->mm);
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}
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return ret;
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}
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void *vmalloc_user(unsigned long size)
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{
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return __vmalloc_user_flags(size, GFP_KERNEL | __GFP_ZERO);
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}
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EXPORT_SYMBOL(vmalloc_user);
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struct page *vmalloc_to_page(const void *addr)
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{
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return virt_to_page(addr);
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}
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EXPORT_SYMBOL(vmalloc_to_page);
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unsigned long vmalloc_to_pfn(const void *addr)
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{
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return page_to_pfn(virt_to_page(addr));
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}
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EXPORT_SYMBOL(vmalloc_to_pfn);
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long vread_iter(struct iov_iter *iter, const char *addr, size_t count)
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{
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/* Don't allow overflow */
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if ((unsigned long) addr + count < count)
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count = -(unsigned long) addr;
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return copy_to_iter(addr, count, iter);
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}
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/*
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* vmalloc - allocate virtually contiguous memory
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*
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* @size: allocation size
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc);
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void *vmalloc_huge(unsigned long size, gfp_t gfp_mask) __weak __alias(__vmalloc);
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/*
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* vzalloc - allocate virtually contiguous memory with zero fill
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*
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* @size: allocation size
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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* The memory allocated is set to zero.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vzalloc(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL | __GFP_ZERO);
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}
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EXPORT_SYMBOL(vzalloc);
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/**
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* vmalloc_node - allocate memory on a specific node
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* @size: allocation size
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* @node: numa node
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vmalloc_node(unsigned long size, int node)
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{
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return vmalloc(size);
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}
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EXPORT_SYMBOL(vmalloc_node);
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/**
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* vzalloc_node - allocate memory on a specific node with zero fill
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* @size: allocation size
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* @node: numa node
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*
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* Allocate enough pages to cover @size from the page level
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* allocator and map them into contiguous kernel virtual space.
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* The memory allocated is set to zero.
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*
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* For tight control over page level allocator and protection flags
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* use __vmalloc() instead.
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*/
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void *vzalloc_node(unsigned long size, int node)
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{
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return vzalloc(size);
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}
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EXPORT_SYMBOL(vzalloc_node);
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/**
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* vmalloc_32 - allocate virtually contiguous memory (32bit addressable)
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* @size: allocation size
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*
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* Allocate enough 32bit PA addressable pages to cover @size from the
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* page level allocator and map them into contiguous kernel virtual space.
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*/
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void *vmalloc_32(unsigned long size)
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{
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return __vmalloc(size, GFP_KERNEL);
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}
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EXPORT_SYMBOL(vmalloc_32);
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/**
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* vmalloc_32_user - allocate zeroed virtually contiguous 32bit memory
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* @size: allocation size
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*
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* The resulting memory area is 32bit addressable and zeroed so it can be
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* mapped to userspace without leaking data.
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*
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* VM_USERMAP is set on the corresponding VMA so that subsequent calls to
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* remap_vmalloc_range() are permissible.
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*/
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void *vmalloc_32_user(unsigned long size)
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{
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/*
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* We'll have to sort out the ZONE_DMA bits for 64-bit,
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* but for now this can simply use vmalloc_user() directly.
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*/
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return vmalloc_user(size);
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}
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EXPORT_SYMBOL(vmalloc_32_user);
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void *vmap(struct page **pages, unsigned int count, unsigned long flags, pgprot_t prot)
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{
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BUG();
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return NULL;
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}
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EXPORT_SYMBOL(vmap);
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void vunmap(const void *addr)
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{
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BUG();
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}
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EXPORT_SYMBOL(vunmap);
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void *vm_map_ram(struct page **pages, unsigned int count, int node)
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{
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BUG();
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return NULL;
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}
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EXPORT_SYMBOL(vm_map_ram);
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void vm_unmap_ram(const void *mem, unsigned int count)
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{
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BUG();
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}
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EXPORT_SYMBOL(vm_unmap_ram);
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void vm_unmap_aliases(void)
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{
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}
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EXPORT_SYMBOL_GPL(vm_unmap_aliases);
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void free_vm_area(struct vm_struct *area)
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{
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BUG();
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}
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EXPORT_SYMBOL_GPL(free_vm_area);
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int vm_insert_page(struct vm_area_struct *vma, unsigned long addr,
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struct page *page)
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{
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return -EINVAL;
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}
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EXPORT_SYMBOL(vm_insert_page);
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int vm_map_pages(struct vm_area_struct *vma, struct page **pages,
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unsigned long num)
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{
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return -EINVAL;
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}
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EXPORT_SYMBOL(vm_map_pages);
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int vm_map_pages_zero(struct vm_area_struct *vma, struct page **pages,
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unsigned long num)
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{
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return -EINVAL;
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}
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EXPORT_SYMBOL(vm_map_pages_zero);
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/*
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* sys_brk() for the most part doesn't need the global kernel
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* lock, except when an application is doing something nasty
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* like trying to un-brk an area that has already been mapped
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* to a regular file. in this case, the unmapping will need
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* to invoke file system routines that need the global lock.
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*/
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SYSCALL_DEFINE1(brk, unsigned long, brk)
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{
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struct mm_struct *mm = current->mm;
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if (brk < mm->start_brk || brk > mm->context.end_brk)
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return mm->brk;
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if (mm->brk == brk)
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return mm->brk;
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/*
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* Always allow shrinking brk
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*/
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if (brk <= mm->brk) {
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mm->brk = brk;
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return brk;
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}
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/*
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* Ok, looks good - let it rip.
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*/
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flush_icache_user_range(mm->brk, brk);
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return mm->brk = brk;
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}
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/*
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* initialise the percpu counter for VM and region record slabs
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*/
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void __init mmap_init(void)
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{
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int ret;
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ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
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VM_BUG_ON(ret);
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vm_region_jar = KMEM_CACHE(vm_region, SLAB_PANIC|SLAB_ACCOUNT);
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}
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/*
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* validate the region tree
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* - the caller must hold the region lock
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*/
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#ifdef CONFIG_DEBUG_NOMMU_REGIONS
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static noinline void validate_nommu_regions(void)
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{
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struct vm_region *region, *last;
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struct rb_node *p, *lastp;
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lastp = rb_first(&nommu_region_tree);
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if (!lastp)
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return;
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last = rb_entry(lastp, struct vm_region, vm_rb);
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BUG_ON(last->vm_end <= last->vm_start);
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BUG_ON(last->vm_top < last->vm_end);
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while ((p = rb_next(lastp))) {
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region = rb_entry(p, struct vm_region, vm_rb);
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last = rb_entry(lastp, struct vm_region, vm_rb);
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BUG_ON(region->vm_end <= region->vm_start);
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BUG_ON(region->vm_top < region->vm_end);
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BUG_ON(region->vm_start < last->vm_top);
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lastp = p;
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}
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}
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#else
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static void validate_nommu_regions(void)
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{
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}
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#endif
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/*
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* add a region into the global tree
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*/
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static void add_nommu_region(struct vm_region *region)
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{
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struct vm_region *pregion;
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struct rb_node **p, *parent;
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validate_nommu_regions();
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parent = NULL;
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p = &nommu_region_tree.rb_node;
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while (*p) {
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parent = *p;
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pregion = rb_entry(parent, struct vm_region, vm_rb);
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if (region->vm_start < pregion->vm_start)
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p = &(*p)->rb_left;
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else if (region->vm_start > pregion->vm_start)
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p = &(*p)->rb_right;
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else if (pregion == region)
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return;
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else
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BUG();
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}
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rb_link_node(®ion->vm_rb, parent, p);
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rb_insert_color(®ion->vm_rb, &nommu_region_tree);
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validate_nommu_regions();
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}
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/*
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* delete a region from the global tree
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*/
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static void delete_nommu_region(struct vm_region *region)
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{
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BUG_ON(!nommu_region_tree.rb_node);
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validate_nommu_regions();
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rb_erase(®ion->vm_rb, &nommu_region_tree);
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validate_nommu_regions();
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}
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/*
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* free a contiguous series of pages
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*/
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static void free_page_series(unsigned long from, unsigned long to)
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{
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for (; from < to; from += PAGE_SIZE) {
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struct page *page = virt_to_page((void *)from);
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atomic_long_dec(&mmap_pages_allocated);
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put_page(page);
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}
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}
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/*
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* release a reference to a region
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* - the caller must hold the region semaphore for writing, which this releases
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* - the region may not have been added to the tree yet, in which case vm_top
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* will equal vm_start
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*/
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static void __put_nommu_region(struct vm_region *region)
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__releases(nommu_region_sem)
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{
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BUG_ON(!nommu_region_tree.rb_node);
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if (--region->vm_usage == 0) {
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if (region->vm_top > region->vm_start)
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delete_nommu_region(region);
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up_write(&nommu_region_sem);
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if (region->vm_file)
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fput(region->vm_file);
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/* IO memory and memory shared directly out of the pagecache
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* from ramfs/tmpfs mustn't be released here */
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if (region->vm_flags & VM_MAPPED_COPY)
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free_page_series(region->vm_start, region->vm_top);
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kmem_cache_free(vm_region_jar, region);
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} else {
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up_write(&nommu_region_sem);
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}
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}
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/*
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* release a reference to a region
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*/
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static void put_nommu_region(struct vm_region *region)
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{
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down_write(&nommu_region_sem);
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__put_nommu_region(region);
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}
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static void setup_vma_to_mm(struct vm_area_struct *vma, struct mm_struct *mm)
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{
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vma->vm_mm = mm;
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/* add the VMA to the mapping */
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if (vma->vm_file) {
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struct address_space *mapping = vma->vm_file->f_mapping;
|
|
|
|
i_mmap_lock_write(mapping);
|
|
flush_dcache_mmap_lock(mapping);
|
|
vma_interval_tree_insert(vma, &mapping->i_mmap);
|
|
flush_dcache_mmap_unlock(mapping);
|
|
i_mmap_unlock_write(mapping);
|
|
}
|
|
}
|
|
|
|
static void cleanup_vma_from_mm(struct vm_area_struct *vma)
|
|
{
|
|
vma->vm_mm->map_count--;
|
|
/* remove the VMA from the mapping */
|
|
if (vma->vm_file) {
|
|
struct address_space *mapping;
|
|
mapping = vma->vm_file->f_mapping;
|
|
|
|
i_mmap_lock_write(mapping);
|
|
flush_dcache_mmap_lock(mapping);
|
|
vma_interval_tree_remove(vma, &mapping->i_mmap);
|
|
flush_dcache_mmap_unlock(mapping);
|
|
i_mmap_unlock_write(mapping);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* delete a VMA from its owning mm_struct and address space
|
|
*/
|
|
static int delete_vma_from_mm(struct vm_area_struct *vma)
|
|
{
|
|
VMA_ITERATOR(vmi, vma->vm_mm, vma->vm_start);
|
|
|
|
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
|
|
if (vma_iter_prealloc(&vmi, NULL)) {
|
|
pr_warn("Allocation of vma tree for process %d failed\n",
|
|
current->pid);
|
|
return -ENOMEM;
|
|
}
|
|
cleanup_vma_from_mm(vma);
|
|
|
|
/* remove from the MM's tree and list */
|
|
vma_iter_clear(&vmi);
|
|
return 0;
|
|
}
|
|
/*
|
|
* destroy a VMA record
|
|
*/
|
|
static void delete_vma(struct mm_struct *mm, struct vm_area_struct *vma)
|
|
{
|
|
vma_close(vma);
|
|
if (vma->vm_file)
|
|
fput(vma->vm_file);
|
|
put_nommu_region(vma->vm_region);
|
|
vm_area_free(vma);
|
|
}
|
|
|
|
struct vm_area_struct *find_vma_intersection(struct mm_struct *mm,
|
|
unsigned long start_addr,
|
|
unsigned long end_addr)
|
|
{
|
|
unsigned long index = start_addr;
|
|
|
|
mmap_assert_locked(mm);
|
|
return mt_find(&mm->mm_mt, &index, end_addr - 1);
|
|
}
|
|
EXPORT_SYMBOL(find_vma_intersection);
|
|
|
|
/*
|
|
* look up the first VMA in which addr resides, NULL if none
|
|
* - should be called with mm->mmap_lock at least held readlocked
|
|
*/
|
|
struct vm_area_struct *find_vma(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
VMA_ITERATOR(vmi, mm, addr);
|
|
|
|
return vma_iter_load(&vmi);
|
|
}
|
|
EXPORT_SYMBOL(find_vma);
|
|
|
|
/*
|
|
* At least xtensa ends up having protection faults even with no
|
|
* MMU.. No stack expansion, at least.
|
|
*/
|
|
struct vm_area_struct *lock_mm_and_find_vma(struct mm_struct *mm,
|
|
unsigned long addr, struct pt_regs *regs)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
mmap_read_lock(mm);
|
|
vma = vma_lookup(mm, addr);
|
|
if (!vma)
|
|
mmap_read_unlock(mm);
|
|
return vma;
|
|
}
|
|
|
|
/*
|
|
* expand a stack to a given address
|
|
* - not supported under NOMMU conditions
|
|
*/
|
|
int expand_stack_locked(struct vm_area_struct *vma, unsigned long addr)
|
|
{
|
|
return -ENOMEM;
|
|
}
|
|
|
|
struct vm_area_struct *expand_stack(struct mm_struct *mm, unsigned long addr)
|
|
{
|
|
mmap_read_unlock(mm);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* look up the first VMA exactly that exactly matches addr
|
|
* - should be called with mm->mmap_lock at least held readlocked
|
|
*/
|
|
static struct vm_area_struct *find_vma_exact(struct mm_struct *mm,
|
|
unsigned long addr,
|
|
unsigned long len)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
unsigned long end = addr + len;
|
|
VMA_ITERATOR(vmi, mm, addr);
|
|
|
|
vma = vma_iter_load(&vmi);
|
|
if (!vma)
|
|
return NULL;
|
|
if (vma->vm_start != addr)
|
|
return NULL;
|
|
if (vma->vm_end != end)
|
|
return NULL;
|
|
|
|
return vma;
|
|
}
|
|
|
|
/*
|
|
* determine whether a mapping should be permitted and, if so, what sort of
|
|
* mapping we're capable of supporting
|
|
*/
|
|
static int validate_mmap_request(struct file *file,
|
|
unsigned long addr,
|
|
unsigned long len,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
unsigned long pgoff,
|
|
unsigned long *_capabilities)
|
|
{
|
|
unsigned long capabilities, rlen;
|
|
int ret;
|
|
|
|
/* do the simple checks first */
|
|
if (flags & MAP_FIXED)
|
|
return -EINVAL;
|
|
|
|
if ((flags & MAP_TYPE) != MAP_PRIVATE &&
|
|
(flags & MAP_TYPE) != MAP_SHARED)
|
|
return -EINVAL;
|
|
|
|
if (!len)
|
|
return -EINVAL;
|
|
|
|
/* Careful about overflows.. */
|
|
rlen = PAGE_ALIGN(len);
|
|
if (!rlen || rlen > TASK_SIZE)
|
|
return -ENOMEM;
|
|
|
|
/* offset overflow? */
|
|
if ((pgoff + (rlen >> PAGE_SHIFT)) < pgoff)
|
|
return -EOVERFLOW;
|
|
|
|
if (file) {
|
|
/* files must support mmap */
|
|
if (!file->f_op->mmap)
|
|
return -ENODEV;
|
|
|
|
/* work out if what we've got could possibly be shared
|
|
* - we support chardevs that provide their own "memory"
|
|
* - we support files/blockdevs that are memory backed
|
|
*/
|
|
if (file->f_op->mmap_capabilities) {
|
|
capabilities = file->f_op->mmap_capabilities(file);
|
|
} else {
|
|
/* no explicit capabilities set, so assume some
|
|
* defaults */
|
|
switch (file_inode(file)->i_mode & S_IFMT) {
|
|
case S_IFREG:
|
|
case S_IFBLK:
|
|
capabilities = NOMMU_MAP_COPY;
|
|
break;
|
|
|
|
case S_IFCHR:
|
|
capabilities =
|
|
NOMMU_MAP_DIRECT |
|
|
NOMMU_MAP_READ |
|
|
NOMMU_MAP_WRITE;
|
|
break;
|
|
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
/* eliminate any capabilities that we can't support on this
|
|
* device */
|
|
if (!file->f_op->get_unmapped_area)
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
if (!(file->f_mode & FMODE_CAN_READ))
|
|
capabilities &= ~NOMMU_MAP_COPY;
|
|
|
|
/* The file shall have been opened with read permission. */
|
|
if (!(file->f_mode & FMODE_READ))
|
|
return -EACCES;
|
|
|
|
if (flags & MAP_SHARED) {
|
|
/* do checks for writing, appending and locking */
|
|
if ((prot & PROT_WRITE) &&
|
|
!(file->f_mode & FMODE_WRITE))
|
|
return -EACCES;
|
|
|
|
if (IS_APPEND(file_inode(file)) &&
|
|
(file->f_mode & FMODE_WRITE))
|
|
return -EACCES;
|
|
|
|
if (!(capabilities & NOMMU_MAP_DIRECT))
|
|
return -ENODEV;
|
|
|
|
/* we mustn't privatise shared mappings */
|
|
capabilities &= ~NOMMU_MAP_COPY;
|
|
} else {
|
|
/* we're going to read the file into private memory we
|
|
* allocate */
|
|
if (!(capabilities & NOMMU_MAP_COPY))
|
|
return -ENODEV;
|
|
|
|
/* we don't permit a private writable mapping to be
|
|
* shared with the backing device */
|
|
if (prot & PROT_WRITE)
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
}
|
|
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
if (((prot & PROT_READ) && !(capabilities & NOMMU_MAP_READ)) ||
|
|
((prot & PROT_WRITE) && !(capabilities & NOMMU_MAP_WRITE)) ||
|
|
((prot & PROT_EXEC) && !(capabilities & NOMMU_MAP_EXEC))
|
|
) {
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
if (flags & MAP_SHARED) {
|
|
pr_warn("MAP_SHARED not completely supported on !MMU\n");
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
}
|
|
|
|
/* handle executable mappings and implied executable
|
|
* mappings */
|
|
if (path_noexec(&file->f_path)) {
|
|
if (prot & PROT_EXEC)
|
|
return -EPERM;
|
|
} else if ((prot & PROT_READ) && !(prot & PROT_EXEC)) {
|
|
/* handle implication of PROT_EXEC by PROT_READ */
|
|
if (current->personality & READ_IMPLIES_EXEC) {
|
|
if (capabilities & NOMMU_MAP_EXEC)
|
|
prot |= PROT_EXEC;
|
|
}
|
|
} else if ((prot & PROT_READ) &&
|
|
(prot & PROT_EXEC) &&
|
|
!(capabilities & NOMMU_MAP_EXEC)
|
|
) {
|
|
/* backing file is not executable, try to copy */
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
}
|
|
} else {
|
|
/* anonymous mappings are always memory backed and can be
|
|
* privately mapped
|
|
*/
|
|
capabilities = NOMMU_MAP_COPY;
|
|
|
|
/* handle PROT_EXEC implication by PROT_READ */
|
|
if ((prot & PROT_READ) &&
|
|
(current->personality & READ_IMPLIES_EXEC))
|
|
prot |= PROT_EXEC;
|
|
}
|
|
|
|
/* allow the security API to have its say */
|
|
ret = security_mmap_addr(addr);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* looks okay */
|
|
*_capabilities = capabilities;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* we've determined that we can make the mapping, now translate what we
|
|
* now know into VMA flags
|
|
*/
|
|
static unsigned long determine_vm_flags(struct file *file,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
unsigned long capabilities)
|
|
{
|
|
unsigned long vm_flags;
|
|
|
|
vm_flags = calc_vm_prot_bits(prot, 0) | calc_vm_flag_bits(file, flags);
|
|
|
|
if (!file) {
|
|
/*
|
|
* MAP_ANONYMOUS. MAP_SHARED is mapped to MAP_PRIVATE, because
|
|
* there is no fork().
|
|
*/
|
|
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
|
|
} else if (flags & MAP_PRIVATE) {
|
|
/* MAP_PRIVATE file mapping */
|
|
if (capabilities & NOMMU_MAP_DIRECT)
|
|
vm_flags |= (capabilities & NOMMU_VMFLAGS);
|
|
else
|
|
vm_flags |= VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC;
|
|
|
|
if (!(prot & PROT_WRITE) && !current->ptrace)
|
|
/*
|
|
* R/O private file mapping which cannot be used to
|
|
* modify memory, especially also not via active ptrace
|
|
* (e.g., set breakpoints) or later by upgrading
|
|
* permissions (no mprotect()). We can try overlaying
|
|
* the file mapping, which will work e.g., on chardevs,
|
|
* ramfs/tmpfs/shmfs and romfs/cramf.
|
|
*/
|
|
vm_flags |= VM_MAYOVERLAY;
|
|
} else {
|
|
/* MAP_SHARED file mapping: NOMMU_MAP_DIRECT is set. */
|
|
vm_flags |= VM_SHARED | VM_MAYSHARE |
|
|
(capabilities & NOMMU_VMFLAGS);
|
|
}
|
|
|
|
return vm_flags;
|
|
}
|
|
|
|
/*
|
|
* set up a shared mapping on a file (the driver or filesystem provides and
|
|
* pins the storage)
|
|
*/
|
|
static int do_mmap_shared_file(struct vm_area_struct *vma)
|
|
{
|
|
int ret;
|
|
|
|
ret = mmap_file(vma->vm_file, vma);
|
|
if (ret == 0) {
|
|
vma->vm_region->vm_top = vma->vm_region->vm_end;
|
|
return 0;
|
|
}
|
|
if (ret != -ENOSYS)
|
|
return ret;
|
|
|
|
/* getting -ENOSYS indicates that direct mmap isn't possible (as
|
|
* opposed to tried but failed) so we can only give a suitable error as
|
|
* it's not possible to make a private copy if MAP_SHARED was given */
|
|
return -ENODEV;
|
|
}
|
|
|
|
/*
|
|
* set up a private mapping or an anonymous shared mapping
|
|
*/
|
|
static int do_mmap_private(struct vm_area_struct *vma,
|
|
struct vm_region *region,
|
|
unsigned long len,
|
|
unsigned long capabilities)
|
|
{
|
|
unsigned long total, point;
|
|
void *base;
|
|
int ret, order;
|
|
|
|
/*
|
|
* Invoke the file's mapping function so that it can keep track of
|
|
* shared mappings on devices or memory. VM_MAYOVERLAY will be set if
|
|
* it may attempt to share, which will make is_nommu_shared_mapping()
|
|
* happy.
|
|
*/
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
ret = mmap_file(vma->vm_file, vma);
|
|
/* shouldn't return success if we're not sharing */
|
|
if (WARN_ON_ONCE(!is_nommu_shared_mapping(vma->vm_flags)))
|
|
ret = -ENOSYS;
|
|
if (ret == 0) {
|
|
vma->vm_region->vm_top = vma->vm_region->vm_end;
|
|
return 0;
|
|
}
|
|
if (ret != -ENOSYS)
|
|
return ret;
|
|
|
|
/* getting an ENOSYS error indicates that direct mmap isn't
|
|
* possible (as opposed to tried but failed) so we'll try to
|
|
* make a private copy of the data and map that instead */
|
|
}
|
|
|
|
|
|
/* allocate some memory to hold the mapping
|
|
* - note that this may not return a page-aligned address if the object
|
|
* we're allocating is smaller than a page
|
|
*/
|
|
order = get_order(len);
|
|
total = 1 << order;
|
|
point = len >> PAGE_SHIFT;
|
|
|
|
/* we don't want to allocate a power-of-2 sized page set */
|
|
if (sysctl_nr_trim_pages && total - point >= sysctl_nr_trim_pages)
|
|
total = point;
|
|
|
|
base = alloc_pages_exact(total << PAGE_SHIFT, GFP_KERNEL);
|
|
if (!base)
|
|
goto enomem;
|
|
|
|
atomic_long_add(total, &mmap_pages_allocated);
|
|
|
|
vm_flags_set(vma, VM_MAPPED_COPY);
|
|
region->vm_flags = vma->vm_flags;
|
|
region->vm_start = (unsigned long) base;
|
|
region->vm_end = region->vm_start + len;
|
|
region->vm_top = region->vm_start + (total << PAGE_SHIFT);
|
|
|
|
vma->vm_start = region->vm_start;
|
|
vma->vm_end = region->vm_start + len;
|
|
|
|
if (vma->vm_file) {
|
|
/* read the contents of a file into the copy */
|
|
loff_t fpos;
|
|
|
|
fpos = vma->vm_pgoff;
|
|
fpos <<= PAGE_SHIFT;
|
|
|
|
ret = kernel_read(vma->vm_file, base, len, &fpos);
|
|
if (ret < 0)
|
|
goto error_free;
|
|
|
|
/* clear the last little bit */
|
|
if (ret < len)
|
|
memset(base + ret, 0, len - ret);
|
|
|
|
} else {
|
|
vma_set_anonymous(vma);
|
|
}
|
|
|
|
return 0;
|
|
|
|
error_free:
|
|
free_page_series(region->vm_start, region->vm_top);
|
|
region->vm_start = vma->vm_start = 0;
|
|
region->vm_end = vma->vm_end = 0;
|
|
region->vm_top = 0;
|
|
return ret;
|
|
|
|
enomem:
|
|
pr_err("Allocation of length %lu from process %d (%s) failed\n",
|
|
len, current->pid, current->comm);
|
|
show_mem();
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* handle mapping creation for uClinux
|
|
*/
|
|
unsigned long do_mmap(struct file *file,
|
|
unsigned long addr,
|
|
unsigned long len,
|
|
unsigned long prot,
|
|
unsigned long flags,
|
|
vm_flags_t vm_flags,
|
|
unsigned long pgoff,
|
|
unsigned long *populate,
|
|
struct list_head *uf)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct vm_region *region;
|
|
struct rb_node *rb;
|
|
unsigned long capabilities, result;
|
|
int ret;
|
|
VMA_ITERATOR(vmi, current->mm, 0);
|
|
|
|
*populate = 0;
|
|
|
|
/* decide whether we should attempt the mapping, and if so what sort of
|
|
* mapping */
|
|
ret = validate_mmap_request(file, addr, len, prot, flags, pgoff,
|
|
&capabilities);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
/* we ignore the address hint */
|
|
addr = 0;
|
|
len = PAGE_ALIGN(len);
|
|
|
|
/* we've determined that we can make the mapping, now translate what we
|
|
* now know into VMA flags */
|
|
vm_flags |= determine_vm_flags(file, prot, flags, capabilities);
|
|
|
|
|
|
/* we're going to need to record the mapping */
|
|
region = kmem_cache_zalloc(vm_region_jar, GFP_KERNEL);
|
|
if (!region)
|
|
goto error_getting_region;
|
|
|
|
vma = vm_area_alloc(current->mm);
|
|
if (!vma)
|
|
goto error_getting_vma;
|
|
|
|
region->vm_usage = 1;
|
|
region->vm_flags = vm_flags;
|
|
region->vm_pgoff = pgoff;
|
|
|
|
vm_flags_init(vma, vm_flags);
|
|
vma->vm_pgoff = pgoff;
|
|
|
|
if (file) {
|
|
region->vm_file = get_file(file);
|
|
vma->vm_file = get_file(file);
|
|
}
|
|
|
|
down_write(&nommu_region_sem);
|
|
|
|
/* if we want to share, we need to check for regions created by other
|
|
* mmap() calls that overlap with our proposed mapping
|
|
* - we can only share with a superset match on most regular files
|
|
* - shared mappings on character devices and memory backed files are
|
|
* permitted to overlap inexactly as far as we are concerned for in
|
|
* these cases, sharing is handled in the driver or filesystem rather
|
|
* than here
|
|
*/
|
|
if (is_nommu_shared_mapping(vm_flags)) {
|
|
struct vm_region *pregion;
|
|
unsigned long pglen, rpglen, pgend, rpgend, start;
|
|
|
|
pglen = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
pgend = pgoff + pglen;
|
|
|
|
for (rb = rb_first(&nommu_region_tree); rb; rb = rb_next(rb)) {
|
|
pregion = rb_entry(rb, struct vm_region, vm_rb);
|
|
|
|
if (!is_nommu_shared_mapping(pregion->vm_flags))
|
|
continue;
|
|
|
|
/* search for overlapping mappings on the same file */
|
|
if (file_inode(pregion->vm_file) !=
|
|
file_inode(file))
|
|
continue;
|
|
|
|
if (pregion->vm_pgoff >= pgend)
|
|
continue;
|
|
|
|
rpglen = pregion->vm_end - pregion->vm_start;
|
|
rpglen = (rpglen + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
rpgend = pregion->vm_pgoff + rpglen;
|
|
if (pgoff >= rpgend)
|
|
continue;
|
|
|
|
/* handle inexactly overlapping matches between
|
|
* mappings */
|
|
if ((pregion->vm_pgoff != pgoff || rpglen != pglen) &&
|
|
!(pgoff >= pregion->vm_pgoff && pgend <= rpgend)) {
|
|
/* new mapping is not a subset of the region */
|
|
if (!(capabilities & NOMMU_MAP_DIRECT))
|
|
goto sharing_violation;
|
|
continue;
|
|
}
|
|
|
|
/* we've found a region we can share */
|
|
pregion->vm_usage++;
|
|
vma->vm_region = pregion;
|
|
start = pregion->vm_start;
|
|
start += (pgoff - pregion->vm_pgoff) << PAGE_SHIFT;
|
|
vma->vm_start = start;
|
|
vma->vm_end = start + len;
|
|
|
|
if (pregion->vm_flags & VM_MAPPED_COPY)
|
|
vm_flags_set(vma, VM_MAPPED_COPY);
|
|
else {
|
|
ret = do_mmap_shared_file(vma);
|
|
if (ret < 0) {
|
|
vma->vm_region = NULL;
|
|
vma->vm_start = 0;
|
|
vma->vm_end = 0;
|
|
pregion->vm_usage--;
|
|
pregion = NULL;
|
|
goto error_just_free;
|
|
}
|
|
}
|
|
fput(region->vm_file);
|
|
kmem_cache_free(vm_region_jar, region);
|
|
region = pregion;
|
|
result = start;
|
|
goto share;
|
|
}
|
|
|
|
/* obtain the address at which to make a shared mapping
|
|
* - this is the hook for quasi-memory character devices to
|
|
* tell us the location of a shared mapping
|
|
*/
|
|
if (capabilities & NOMMU_MAP_DIRECT) {
|
|
addr = file->f_op->get_unmapped_area(file, addr, len,
|
|
pgoff, flags);
|
|
if (IS_ERR_VALUE(addr)) {
|
|
ret = addr;
|
|
if (ret != -ENOSYS)
|
|
goto error_just_free;
|
|
|
|
/* the driver refused to tell us where to site
|
|
* the mapping so we'll have to attempt to copy
|
|
* it */
|
|
ret = -ENODEV;
|
|
if (!(capabilities & NOMMU_MAP_COPY))
|
|
goto error_just_free;
|
|
|
|
capabilities &= ~NOMMU_MAP_DIRECT;
|
|
} else {
|
|
vma->vm_start = region->vm_start = addr;
|
|
vma->vm_end = region->vm_end = addr + len;
|
|
}
|
|
}
|
|
}
|
|
|
|
vma->vm_region = region;
|
|
|
|
/* set up the mapping
|
|
* - the region is filled in if NOMMU_MAP_DIRECT is still set
|
|
*/
|
|
if (file && vma->vm_flags & VM_SHARED)
|
|
ret = do_mmap_shared_file(vma);
|
|
else
|
|
ret = do_mmap_private(vma, region, len, capabilities);
|
|
if (ret < 0)
|
|
goto error_just_free;
|
|
add_nommu_region(region);
|
|
|
|
/* clear anonymous mappings that don't ask for uninitialized data */
|
|
if (!vma->vm_file &&
|
|
(!IS_ENABLED(CONFIG_MMAP_ALLOW_UNINITIALIZED) ||
|
|
!(flags & MAP_UNINITIALIZED)))
|
|
memset((void *)region->vm_start, 0,
|
|
region->vm_end - region->vm_start);
|
|
|
|
/* okay... we have a mapping; now we have to register it */
|
|
result = vma->vm_start;
|
|
|
|
current->mm->total_vm += len >> PAGE_SHIFT;
|
|
|
|
share:
|
|
BUG_ON(!vma->vm_region);
|
|
vma_iter_config(&vmi, vma->vm_start, vma->vm_end);
|
|
if (vma_iter_prealloc(&vmi, vma))
|
|
goto error_just_free;
|
|
|
|
setup_vma_to_mm(vma, current->mm);
|
|
current->mm->map_count++;
|
|
/* add the VMA to the tree */
|
|
vma_iter_store(&vmi, vma);
|
|
|
|
/* we flush the region from the icache only when the first executable
|
|
* mapping of it is made */
|
|
if (vma->vm_flags & VM_EXEC && !region->vm_icache_flushed) {
|
|
flush_icache_user_range(region->vm_start, region->vm_end);
|
|
region->vm_icache_flushed = true;
|
|
}
|
|
|
|
up_write(&nommu_region_sem);
|
|
|
|
return result;
|
|
|
|
error_just_free:
|
|
up_write(&nommu_region_sem);
|
|
error:
|
|
vma_iter_free(&vmi);
|
|
if (region->vm_file)
|
|
fput(region->vm_file);
|
|
kmem_cache_free(vm_region_jar, region);
|
|
if (vma->vm_file)
|
|
fput(vma->vm_file);
|
|
vm_area_free(vma);
|
|
return ret;
|
|
|
|
sharing_violation:
|
|
up_write(&nommu_region_sem);
|
|
pr_warn("Attempt to share mismatched mappings\n");
|
|
ret = -EINVAL;
|
|
goto error;
|
|
|
|
error_getting_vma:
|
|
kmem_cache_free(vm_region_jar, region);
|
|
pr_warn("Allocation of vma for %lu byte allocation from process %d failed\n",
|
|
len, current->pid);
|
|
show_mem();
|
|
return -ENOMEM;
|
|
|
|
error_getting_region:
|
|
pr_warn("Allocation of vm region for %lu byte allocation from process %d failed\n",
|
|
len, current->pid);
|
|
show_mem();
|
|
return -ENOMEM;
|
|
}
|
|
|
|
unsigned long ksys_mmap_pgoff(unsigned long addr, unsigned long len,
|
|
unsigned long prot, unsigned long flags,
|
|
unsigned long fd, unsigned long pgoff)
|
|
{
|
|
struct file *file = NULL;
|
|
unsigned long retval = -EBADF;
|
|
|
|
audit_mmap_fd(fd, flags);
|
|
if (!(flags & MAP_ANONYMOUS)) {
|
|
file = fget(fd);
|
|
if (!file)
|
|
goto out;
|
|
}
|
|
|
|
retval = vm_mmap_pgoff(file, addr, len, prot, flags, pgoff);
|
|
|
|
if (file)
|
|
fput(file);
|
|
out:
|
|
return retval;
|
|
}
|
|
|
|
SYSCALL_DEFINE6(mmap_pgoff, unsigned long, addr, unsigned long, len,
|
|
unsigned long, prot, unsigned long, flags,
|
|
unsigned long, fd, unsigned long, pgoff)
|
|
{
|
|
return ksys_mmap_pgoff(addr, len, prot, flags, fd, pgoff);
|
|
}
|
|
|
|
#ifdef __ARCH_WANT_SYS_OLD_MMAP
|
|
struct mmap_arg_struct {
|
|
unsigned long addr;
|
|
unsigned long len;
|
|
unsigned long prot;
|
|
unsigned long flags;
|
|
unsigned long fd;
|
|
unsigned long offset;
|
|
};
|
|
|
|
SYSCALL_DEFINE1(old_mmap, struct mmap_arg_struct __user *, arg)
|
|
{
|
|
struct mmap_arg_struct a;
|
|
|
|
if (copy_from_user(&a, arg, sizeof(a)))
|
|
return -EFAULT;
|
|
if (offset_in_page(a.offset))
|
|
return -EINVAL;
|
|
|
|
return ksys_mmap_pgoff(a.addr, a.len, a.prot, a.flags, a.fd,
|
|
a.offset >> PAGE_SHIFT);
|
|
}
|
|
#endif /* __ARCH_WANT_SYS_OLD_MMAP */
|
|
|
|
/*
|
|
* split a vma into two pieces at address 'addr', a new vma is allocated either
|
|
* for the first part or the tail.
|
|
*/
|
|
int split_vma(struct vma_iterator *vmi, struct vm_area_struct *vma,
|
|
unsigned long addr, int new_below)
|
|
{
|
|
struct vm_area_struct *new;
|
|
struct vm_region *region;
|
|
unsigned long npages;
|
|
struct mm_struct *mm;
|
|
|
|
/* we're only permitted to split anonymous regions (these should have
|
|
* only a single usage on the region) */
|
|
if (vma->vm_file)
|
|
return -ENOMEM;
|
|
|
|
mm = vma->vm_mm;
|
|
if (mm->map_count >= sysctl_max_map_count)
|
|
return -ENOMEM;
|
|
|
|
region = kmem_cache_alloc(vm_region_jar, GFP_KERNEL);
|
|
if (!region)
|
|
return -ENOMEM;
|
|
|
|
new = vm_area_dup(vma);
|
|
if (!new)
|
|
goto err_vma_dup;
|
|
|
|
/* most fields are the same, copy all, and then fixup */
|
|
*region = *vma->vm_region;
|
|
new->vm_region = region;
|
|
|
|
npages = (addr - vma->vm_start) >> PAGE_SHIFT;
|
|
|
|
if (new_below) {
|
|
region->vm_top = region->vm_end = new->vm_end = addr;
|
|
} else {
|
|
region->vm_start = new->vm_start = addr;
|
|
region->vm_pgoff = new->vm_pgoff += npages;
|
|
}
|
|
|
|
vma_iter_config(vmi, new->vm_start, new->vm_end);
|
|
if (vma_iter_prealloc(vmi, vma)) {
|
|
pr_warn("Allocation of vma tree for process %d failed\n",
|
|
current->pid);
|
|
goto err_vmi_preallocate;
|
|
}
|
|
|
|
if (new->vm_ops && new->vm_ops->open)
|
|
new->vm_ops->open(new);
|
|
|
|
down_write(&nommu_region_sem);
|
|
delete_nommu_region(vma->vm_region);
|
|
if (new_below) {
|
|
vma->vm_region->vm_start = vma->vm_start = addr;
|
|
vma->vm_region->vm_pgoff = vma->vm_pgoff += npages;
|
|
} else {
|
|
vma->vm_region->vm_end = vma->vm_end = addr;
|
|
vma->vm_region->vm_top = addr;
|
|
}
|
|
add_nommu_region(vma->vm_region);
|
|
add_nommu_region(new->vm_region);
|
|
up_write(&nommu_region_sem);
|
|
|
|
setup_vma_to_mm(vma, mm);
|
|
setup_vma_to_mm(new, mm);
|
|
vma_iter_store(vmi, new);
|
|
mm->map_count++;
|
|
return 0;
|
|
|
|
err_vmi_preallocate:
|
|
vm_area_free(new);
|
|
err_vma_dup:
|
|
kmem_cache_free(vm_region_jar, region);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* shrink a VMA by removing the specified chunk from either the beginning or
|
|
* the end
|
|
*/
|
|
static int vmi_shrink_vma(struct vma_iterator *vmi,
|
|
struct vm_area_struct *vma,
|
|
unsigned long from, unsigned long to)
|
|
{
|
|
struct vm_region *region;
|
|
|
|
/* adjust the VMA's pointers, which may reposition it in the MM's tree
|
|
* and list */
|
|
if (from > vma->vm_start) {
|
|
if (vma_iter_clear_gfp(vmi, from, vma->vm_end, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
vma->vm_end = from;
|
|
} else {
|
|
if (vma_iter_clear_gfp(vmi, vma->vm_start, to, GFP_KERNEL))
|
|
return -ENOMEM;
|
|
vma->vm_start = to;
|
|
}
|
|
|
|
/* cut the backing region down to size */
|
|
region = vma->vm_region;
|
|
BUG_ON(region->vm_usage != 1);
|
|
|
|
down_write(&nommu_region_sem);
|
|
delete_nommu_region(region);
|
|
if (from > region->vm_start) {
|
|
to = region->vm_top;
|
|
region->vm_top = region->vm_end = from;
|
|
} else {
|
|
region->vm_start = to;
|
|
}
|
|
add_nommu_region(region);
|
|
up_write(&nommu_region_sem);
|
|
|
|
free_page_series(from, to);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* release a mapping
|
|
* - under NOMMU conditions the chunk to be unmapped must be backed by a single
|
|
* VMA, though it need not cover the whole VMA
|
|
*/
|
|
int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
|
|
{
|
|
VMA_ITERATOR(vmi, mm, start);
|
|
struct vm_area_struct *vma;
|
|
unsigned long end;
|
|
int ret = 0;
|
|
|
|
len = PAGE_ALIGN(len);
|
|
if (len == 0)
|
|
return -EINVAL;
|
|
|
|
end = start + len;
|
|
|
|
/* find the first potentially overlapping VMA */
|
|
vma = vma_find(&vmi, end);
|
|
if (!vma) {
|
|
static int limit;
|
|
if (limit < 5) {
|
|
pr_warn("munmap of memory not mmapped by process %d (%s): 0x%lx-0x%lx\n",
|
|
current->pid, current->comm,
|
|
start, start + len - 1);
|
|
limit++;
|
|
}
|
|
return -EINVAL;
|
|
}
|
|
|
|
/* we're allowed to split an anonymous VMA but not a file-backed one */
|
|
if (vma->vm_file) {
|
|
do {
|
|
if (start > vma->vm_start)
|
|
return -EINVAL;
|
|
if (end == vma->vm_end)
|
|
goto erase_whole_vma;
|
|
vma = vma_find(&vmi, end);
|
|
} while (vma);
|
|
return -EINVAL;
|
|
} else {
|
|
/* the chunk must be a subset of the VMA found */
|
|
if (start == vma->vm_start && end == vma->vm_end)
|
|
goto erase_whole_vma;
|
|
if (start < vma->vm_start || end > vma->vm_end)
|
|
return -EINVAL;
|
|
if (offset_in_page(start))
|
|
return -EINVAL;
|
|
if (end != vma->vm_end && offset_in_page(end))
|
|
return -EINVAL;
|
|
if (start != vma->vm_start && end != vma->vm_end) {
|
|
ret = split_vma(&vmi, vma, start, 1);
|
|
if (ret < 0)
|
|
return ret;
|
|
}
|
|
return vmi_shrink_vma(&vmi, vma, start, end);
|
|
}
|
|
|
|
erase_whole_vma:
|
|
if (delete_vma_from_mm(vma))
|
|
ret = -ENOMEM;
|
|
else
|
|
delete_vma(mm, vma);
|
|
return ret;
|
|
}
|
|
|
|
int vm_munmap(unsigned long addr, size_t len)
|
|
{
|
|
struct mm_struct *mm = current->mm;
|
|
int ret;
|
|
|
|
mmap_write_lock(mm);
|
|
ret = do_munmap(mm, addr, len, NULL);
|
|
mmap_write_unlock(mm);
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(vm_munmap);
|
|
|
|
SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
|
|
{
|
|
return vm_munmap(addr, len);
|
|
}
|
|
|
|
/*
|
|
* release all the mappings made in a process's VM space
|
|
*/
|
|
void exit_mmap(struct mm_struct *mm)
|
|
{
|
|
VMA_ITERATOR(vmi, mm, 0);
|
|
struct vm_area_struct *vma;
|
|
|
|
if (!mm)
|
|
return;
|
|
|
|
mm->total_vm = 0;
|
|
|
|
/*
|
|
* Lock the mm to avoid assert complaining even though this is the only
|
|
* user of the mm
|
|
*/
|
|
mmap_write_lock(mm);
|
|
for_each_vma(vmi, vma) {
|
|
cleanup_vma_from_mm(vma);
|
|
delete_vma(mm, vma);
|
|
cond_resched();
|
|
}
|
|
__mt_destroy(&mm->mm_mt);
|
|
mmap_write_unlock(mm);
|
|
}
|
|
|
|
int vm_brk(unsigned long addr, unsigned long len)
|
|
{
|
|
return -ENOMEM;
|
|
}
|
|
|
|
/*
|
|
* expand (or shrink) an existing mapping, potentially moving it at the same
|
|
* time (controlled by the MREMAP_MAYMOVE flag and available VM space)
|
|
*
|
|
* under NOMMU conditions, we only permit changing a mapping's size, and only
|
|
* as long as it stays within the region allocated by do_mmap_private() and the
|
|
* block is not shareable
|
|
*
|
|
* MREMAP_FIXED is not supported under NOMMU conditions
|
|
*/
|
|
static unsigned long do_mremap(unsigned long addr,
|
|
unsigned long old_len, unsigned long new_len,
|
|
unsigned long flags, unsigned long new_addr)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
|
|
/* insanity checks first */
|
|
old_len = PAGE_ALIGN(old_len);
|
|
new_len = PAGE_ALIGN(new_len);
|
|
if (old_len == 0 || new_len == 0)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
if (offset_in_page(addr))
|
|
return -EINVAL;
|
|
|
|
if (flags & MREMAP_FIXED && new_addr != addr)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
vma = find_vma_exact(current->mm, addr, old_len);
|
|
if (!vma)
|
|
return (unsigned long) -EINVAL;
|
|
|
|
if (vma->vm_end != vma->vm_start + old_len)
|
|
return (unsigned long) -EFAULT;
|
|
|
|
if (is_nommu_shared_mapping(vma->vm_flags))
|
|
return (unsigned long) -EPERM;
|
|
|
|
if (new_len > vma->vm_region->vm_end - vma->vm_region->vm_start)
|
|
return (unsigned long) -ENOMEM;
|
|
|
|
/* all checks complete - do it */
|
|
vma->vm_end = vma->vm_start + new_len;
|
|
return vma->vm_start;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len,
|
|
unsigned long, new_len, unsigned long, flags,
|
|
unsigned long, new_addr)
|
|
{
|
|
unsigned long ret;
|
|
|
|
mmap_write_lock(current->mm);
|
|
ret = do_mremap(addr, old_len, new_len, flags, new_addr);
|
|
mmap_write_unlock(current->mm);
|
|
return ret;
|
|
}
|
|
|
|
struct page *follow_page(struct vm_area_struct *vma, unsigned long address,
|
|
unsigned int foll_flags)
|
|
{
|
|
return NULL;
|
|
}
|
|
|
|
int remap_pfn_range(struct vm_area_struct *vma, unsigned long addr,
|
|
unsigned long pfn, unsigned long size, pgprot_t prot)
|
|
{
|
|
if (addr != (pfn << PAGE_SHIFT))
|
|
return -EINVAL;
|
|
|
|
vm_flags_set(vma, VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP);
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(remap_pfn_range);
|
|
|
|
int vm_iomap_memory(struct vm_area_struct *vma, phys_addr_t start, unsigned long len)
|
|
{
|
|
unsigned long pfn = start >> PAGE_SHIFT;
|
|
unsigned long vm_len = vma->vm_end - vma->vm_start;
|
|
|
|
pfn += vma->vm_pgoff;
|
|
return io_remap_pfn_range(vma, vma->vm_start, pfn, vm_len, vma->vm_page_prot);
|
|
}
|
|
EXPORT_SYMBOL(vm_iomap_memory);
|
|
|
|
int remap_vmalloc_range(struct vm_area_struct *vma, void *addr,
|
|
unsigned long pgoff)
|
|
{
|
|
unsigned int size = vma->vm_end - vma->vm_start;
|
|
|
|
if (!(vma->vm_flags & VM_USERMAP))
|
|
return -EINVAL;
|
|
|
|
vma->vm_start = (unsigned long)(addr + (pgoff << PAGE_SHIFT));
|
|
vma->vm_end = vma->vm_start + size;
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(remap_vmalloc_range);
|
|
|
|
vm_fault_t filemap_fault(struct vm_fault *vmf)
|
|
{
|
|
BUG();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(filemap_fault);
|
|
|
|
vm_fault_t filemap_map_pages(struct vm_fault *vmf,
|
|
pgoff_t start_pgoff, pgoff_t end_pgoff)
|
|
{
|
|
BUG();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(filemap_map_pages);
|
|
|
|
int __access_remote_vm(struct mm_struct *mm, unsigned long addr, void *buf,
|
|
int len, unsigned int gup_flags)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
int write = gup_flags & FOLL_WRITE;
|
|
|
|
if (mmap_read_lock_killable(mm))
|
|
return 0;
|
|
|
|
/* the access must start within one of the target process's mappings */
|
|
vma = find_vma(mm, addr);
|
|
if (vma) {
|
|
/* don't overrun this mapping */
|
|
if (addr + len >= vma->vm_end)
|
|
len = vma->vm_end - addr;
|
|
|
|
/* only read or write mappings where it is permitted */
|
|
if (write && vma->vm_flags & VM_MAYWRITE)
|
|
copy_to_user_page(vma, NULL, addr,
|
|
(void *) addr, buf, len);
|
|
else if (!write && vma->vm_flags & VM_MAYREAD)
|
|
copy_from_user_page(vma, NULL, addr,
|
|
buf, (void *) addr, len);
|
|
else
|
|
len = 0;
|
|
} else {
|
|
len = 0;
|
|
}
|
|
|
|
mmap_read_unlock(mm);
|
|
|
|
return len;
|
|
}
|
|
|
|
/**
|
|
* access_remote_vm - access another process' address space
|
|
* @mm: the mm_struct of the target address space
|
|
* @addr: start address to access
|
|
* @buf: source or destination buffer
|
|
* @len: number of bytes to transfer
|
|
* @gup_flags: flags modifying lookup behaviour
|
|
*
|
|
* The caller must hold a reference on @mm.
|
|
*/
|
|
int access_remote_vm(struct mm_struct *mm, unsigned long addr,
|
|
void *buf, int len, unsigned int gup_flags)
|
|
{
|
|
return __access_remote_vm(mm, addr, buf, len, gup_flags);
|
|
}
|
|
|
|
/*
|
|
* Access another process' address space.
|
|
* - source/target buffer must be kernel space
|
|
*/
|
|
int access_process_vm(struct task_struct *tsk, unsigned long addr, void *buf, int len,
|
|
unsigned int gup_flags)
|
|
{
|
|
struct mm_struct *mm;
|
|
|
|
if (addr + len < addr)
|
|
return 0;
|
|
|
|
mm = get_task_mm(tsk);
|
|
if (!mm)
|
|
return 0;
|
|
|
|
len = __access_remote_vm(mm, addr, buf, len, gup_flags);
|
|
|
|
mmput(mm);
|
|
return len;
|
|
}
|
|
EXPORT_SYMBOL_GPL(access_process_vm);
|
|
|
|
/**
|
|
* nommu_shrink_inode_mappings - Shrink the shared mappings on an inode
|
|
* @inode: The inode to check
|
|
* @size: The current filesize of the inode
|
|
* @newsize: The proposed filesize of the inode
|
|
*
|
|
* Check the shared mappings on an inode on behalf of a shrinking truncate to
|
|
* make sure that any outstanding VMAs aren't broken and then shrink the
|
|
* vm_regions that extend beyond so that do_mmap() doesn't
|
|
* automatically grant mappings that are too large.
|
|
*/
|
|
int nommu_shrink_inode_mappings(struct inode *inode, size_t size,
|
|
size_t newsize)
|
|
{
|
|
struct vm_area_struct *vma;
|
|
struct vm_region *region;
|
|
pgoff_t low, high;
|
|
size_t r_size, r_top;
|
|
|
|
low = newsize >> PAGE_SHIFT;
|
|
high = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
|
|
down_write(&nommu_region_sem);
|
|
i_mmap_lock_read(inode->i_mapping);
|
|
|
|
/* search for VMAs that fall within the dead zone */
|
|
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, low, high) {
|
|
/* found one - only interested if it's shared out of the page
|
|
* cache */
|
|
if (vma->vm_flags & VM_SHARED) {
|
|
i_mmap_unlock_read(inode->i_mapping);
|
|
up_write(&nommu_region_sem);
|
|
return -ETXTBSY; /* not quite true, but near enough */
|
|
}
|
|
}
|
|
|
|
/* reduce any regions that overlap the dead zone - if in existence,
|
|
* these will be pointed to by VMAs that don't overlap the dead zone
|
|
*
|
|
* we don't check for any regions that start beyond the EOF as there
|
|
* shouldn't be any
|
|
*/
|
|
vma_interval_tree_foreach(vma, &inode->i_mapping->i_mmap, 0, ULONG_MAX) {
|
|
if (!(vma->vm_flags & VM_SHARED))
|
|
continue;
|
|
|
|
region = vma->vm_region;
|
|
r_size = region->vm_top - region->vm_start;
|
|
r_top = (region->vm_pgoff << PAGE_SHIFT) + r_size;
|
|
|
|
if (r_top > newsize) {
|
|
region->vm_top -= r_top - newsize;
|
|
if (region->vm_end > region->vm_top)
|
|
region->vm_end = region->vm_top;
|
|
}
|
|
}
|
|
|
|
i_mmap_unlock_read(inode->i_mapping);
|
|
up_write(&nommu_region_sem);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Initialise sysctl_user_reserve_kbytes.
|
|
*
|
|
* This is intended to prevent a user from starting a single memory hogging
|
|
* process, such that they cannot recover (kill the hog) in OVERCOMMIT_NEVER
|
|
* mode.
|
|
*
|
|
* The default value is min(3% of free memory, 128MB)
|
|
* 128MB is enough to recover with sshd/login, bash, and top/kill.
|
|
*/
|
|
static int __meminit init_user_reserve(void)
|
|
{
|
|
unsigned long free_kbytes;
|
|
|
|
free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
|
|
|
|
sysctl_user_reserve_kbytes = min(free_kbytes / 32, 1UL << 17);
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_user_reserve);
|
|
|
|
/*
|
|
* Initialise sysctl_admin_reserve_kbytes.
|
|
*
|
|
* The purpose of sysctl_admin_reserve_kbytes is to allow the sys admin
|
|
* to log in and kill a memory hogging process.
|
|
*
|
|
* Systems with more than 256MB will reserve 8MB, enough to recover
|
|
* with sshd, bash, and top in OVERCOMMIT_GUESS. Smaller systems will
|
|
* only reserve 3% of free pages by default.
|
|
*/
|
|
static int __meminit init_admin_reserve(void)
|
|
{
|
|
unsigned long free_kbytes;
|
|
|
|
free_kbytes = K(global_zone_page_state(NR_FREE_PAGES));
|
|
|
|
sysctl_admin_reserve_kbytes = min(free_kbytes / 32, 1UL << 13);
|
|
return 0;
|
|
}
|
|
subsys_initcall(init_admin_reserve);
|